1. Field of the Invention
The present invention generally relates to a dispenser for a chemical-mechanical polishing (hereinafter abbreviated as CMP) apparatus, a CMP apparatus having the dispenser, and a CMP process using the CMP apparatus, and more particularly, to a slurry and rinse dispenser for a CMP apparatus, a CMP apparatus having the dispenser, and a CMP process using the CMP apparatus.
2. Description of the Prior Art
Integrated circuits (ICs) are typically formed on substrates, exemplarily silicon wafers, by sequential deposition of conductive, semi-conductive or insulating layers. After depositing the required layer, etching process is often performed to create circuitry features and followed by another film formation. Consequently, the topmost surface of the substrate may become non-planar across its surface and requires planarization.
CMP is one accepted method of planarization and now typically employed in the industry. In general, CMP involves pressing a surface of the substrate against a polishing pad that is mounted upon a circular turning platen with a polishing head tightly holds the substrate. Slurries, usually either are basic or acidic and generally contain particles, are delivered to the center of the polishing pad to chemically passivate or oxidize the surface being polished and abrasively remove or polish off the surface of the substrate. The interaction of the polishing pad and the slurries with the surface being polished results in controlled polishing of the desired surface for subsequent processes.
Please refer to FIG. 1, which is a graph depicting removal rates versus distance from a wafer center to wafer edges using a conventional CMP apparatus. One problem is encountered in the CMP process using the conventional CMP apparatus when the slurry is delivered to the center of the polishing pad. In detail, because the slurry is delivered to only the center of the polishing pad in the conventional CMP apparatus, the slurry is not uniformly distributed. Accordingly, both general decrease in removal rate and lack of uniformity in removal rate on different regions of the polishing pad are caused. As shown in FIG. 1, the removal rate at the wafer center is significantly higher than the removal rate near the wafer edges. Accordingly, significant and costly reduction in CMP process efficiency and product quality are resulted.